Two sisters who went to school with Chapman emailed the Maryland attorney general's office with their claims that she is lying. Chapman offered her testimony earlier this summer as part of Syed's efforts to bring his case back to court. Syed has since been granted a retrial of his conviction in the 1999 murder of his ex-girlfriend Hae Min Lee.

Chapman, who maintains that she saw Syed in the school library at the time of Lee's death, addressed the sisters' accusations in a statement posted to her website. According to Chapman, she and the sisters had enjoyed a "positive, friendly" relationship after meeting in high school. More recently, she reconnected with the sisters on Facebook to confirm a photograph and other details for her book, Confessions of a Serial Alibi.

"Five months later, after the publication of my internationally recognized memoir and increasing media attention, I received a message from sister #1," she wrote. "This time the message was abrasive and completely out of character from what I had come to expect from her. In the message she accused me of wrongdoing in connection with the Adnan Syed investigation and questioned my validity as a potential alibi witness for Mr. Syed. Dumbfounded by her newfound accusations and feeling them to be both bizarre and untrue, I naturally assumed that her Facebook account had been hacked and that I was once again being targeted for cyberbullying. I tried to respond to the message, but found that I had already been blocked.

"I immediately sent a message to sister #2 asking if sister #1’s Facebook account had been hacked because of the language and ideals expressed (not to mention Facebook accounts get hacked all the time). It was at that time that sister #2 proceeded to verbally attack me and she too blocked me, once I denied such allegations.

"It has been with great dismay that I read these entirely false allegations from these two sisters and it is with great sadness that I am now forced to question the true purpose and motivations behind these awful and untrue allegations. I have never wavered in my recollection of the events surrounding the murder of Ms. Lee."

Chapman also shared screenshots of her communications with the two sisters. It is unclear how these allegations might impact Syed's retrial.